I’m a little surprised that so many smart people working with large research grants have not produced more useful information on controlling SWD, especially over the past several years.
Looks like the best info available for the commercial grower is: Start spraying when fruit turns color, spray every week, rotate labeled chemicals between different classes to help reduced resistance, keep all ripe fruit picked and traditional IPM strategies don’t work on SWD.
Rick,
I’ve also found that picking up all the peach drops helps a lot. SWD is a lot harder to control if we get behind picking up and disposing of drops. You can’t just leave the drops in piles either. They have to be buried, or some other means of disposal. I throw drops in a small hole which has water in it.
Contrary to has sometimes been reported, MSU confirmed that SWD will lay eggs in drops.
Olpea
Thanks for mentioning the peaches. Do you have a separate spray program for SWD on Peaches or does your normal cover spray program take care of the SWD too.
I need to worry more about SWD on Peaches
Peaches and plums, too, apparently
Really hard to pick up all the plum drops before pests can get to them
Yes, SWD will lay eggs in just about anything. They were flourishing in persimmon drops throughout the summer. They even layed eggs in aborted zucchini flowers!
I do cover sprays on the peaches. I think that helps. But the biggest reduction in pest pressure is to pick up drops daily. By the end of summer, we are pretty exhausted and aren’t as diligent about picking up drops. That’s when we see problems with SWD in peaches, if we aren’t careful. You will see some small slightly sunken spots on soft peaches. The small sunken spots are softer still and there may be some very small breaks in the skin at those spots. That’s SWD.
It’s pretty easy to see if the SWD pressure is high in the orchard, simply by seeing the amount of gnats in the trees. Of course not all the gnats are SWD, but I’ve found a pretty strong correlation between observations of regular fruit flies (which attack over-ripe fruit) and SWD. Apparently they prefer the same conditions.
If it’s a problem, we simply start picking peaches a little firmer. Blackberries don’t have to be soft for SWD to attack them, but SWD will leave firmer peaches alone. Peaches don’t have to be super firm to stop SWD, just firm enough you wouldn’t want to eat them without ripening on the kitchen counter for a couple days.
They are all poison, so no choices there…pyrethrum that is biodegradable is no good in warm weather and resistance already developed in Calif. …there are basically 2 choices …give up ideas of growing fruit or consume lots of poison. And ALL of the effective pesticides are toxic to bees…I’ve been reading about SWD…there is no good news angle to this pest…nothing.
Actually Entrust (spinosad) is much less toxic to bees than alternative chemicals. The label indicates it toxic to bees for 3 hours after spraying which is much better than any effective chemical I have seen.
Some research has showed that a synthetic sweetner (I cant remember which one) has some effect on SWD too.
I made some really good elderberry syrup…more like a concentrated juice last year…just finishing it now…picking all the stems out is fussy …but the product made me think it is definitely worth it…it is so good. I was thinking of increasing my elderberries…but I now read that SWD love elderberries. I have wanted to do this since I was a teenager…finally got the chance 7 years ago…now at age 55 …on top of all the existing challenges of growing fruit. (organically)…which is a lot, but something I was willing to courageously tackle and dedicate all my off work hours to…we now have the additional challenges of climate change and now SWD. Depressing…
its a sugar alcohol. i don’t remember the name either. starts with a e.
I’m more worried about these invasive insects that keep coming here than climate change. they said the costal cities would be under water by 2013. they’re still here, high n’ dry. 
Well…I know this doesn’t apply to SWD as it truly is just an invasive species that will take up residence anywhere that approximates it’s natural habitat…but the two things will likely be connected and a concern in years to come (climate change and pests)…for now, …for now, most of the flooded fields are setting back farmers’ planting , but are **mostly gone by the time the fruit trees are waking up…for now…If it gets much worse, we may see standing water as the fruit trees wake up and that will not be good. We are seeing exceptionally wet late winter/early spring here and only promises to get worse…and although this area has always had summer droughts…that too is worsening…climate change may well bring new growing opportunities, but there won’t be anything benefitting from weather extremes.
they say on OMAFRA site that most of the haskap crops are spared as they are finished by the time SWD get going…I wish I knew that before I put in another 30 (late variety) plants last year. They will be ripening in SWD season.
There is a whole series of updated info (Published December 2019) from Oregon State University
About this series
This publication is one of a series of nine publications focused on strategies for controlling spotted-wing drosophila in Oregon. Find them at https://catalog.extension.oregonstate.edu/. The publications in this series include:
- EM 9261: How Seasons Affect Population Structure, Behavior and Risk on Spotted-wing Drosophila
- EM 9262: Cultural Control Strategies to Manage Spotted-wing Drosophila
- EM 9263: Host Range and Characteristics Affecting Fruit Susceptibility to Spotted-wing Drosophila
- EM 9264 Noncrop Host Plants Used By Spotted-wing Drosophila
- EM 9265: Chemical Control of Spotted-wing Drosophila: Spray Applications
- EM 9266: Chemical Control of Spotted-wing Drosophila: Insecticide Efficacy
- EM 9267: Monitoring Techniques for Spotted-wing Drosophila
- EM 9268: Potential Impacts of Irrigation on Biocontrol on Spotted-wing Drosophila Populations
- EM 9269: Biocontrol of Spotted-wing Drosophila
Some highlights:
thats why i ordered another aurora and honey bee instead of the blizzard and beast. same reason I’m culling some of my fall bearing rasps and replacing with summer bearing. SWD hasn’t shown up here yet but i think it will eventually. I’m surrounded by wild late summer fruit like chokecherry, mtn ash, pin cherry and highbush cranberry so once it gets established here, its here to stay!
I believe in a back yard orchard situation you could just aggressively pick all ripe fruit and soak the fruit in a salt water solution to remove the maggots similar to soaking broccoli in salt water to remove the worms.
The entomologist is scheduled to speak at a grower seminar in a few weeks and I will pass along any new information on SWD that is discussed. Should be quite a few certified organic growers at the meeting so any new info may involve options other than synthetic chemicals
It’s called erythritol. There was a lot of hoopla over it at first, but it doesn’t have a lot of impact if used as a synergist with other insecticides.
Amperstand posted a topic on methyl benzoate as a possible backyard solution. It’s frightfully expensive from a commercial standpoint, but could have some application in a smaller backyard planting.
Evidently this Methyl Benzoate is the chemical that drug sniffing dogs actually seek out when sniffing for cocaine. So be careful if taking fruits sprayed with it on a trip to the airport…lol
It also supposedly smells like pineapple guava.
I need to be better at keeping up with drops evidently…
Scott
This didn’t work for my raspberries last year. By the time they fully ripen they would be too soft to pick and slightly fermented. Strawberries would also get way too soft by the time they get fully ripe.
